I'm interested in distressed hotel transactions, and would like advice from someone who has done this please.
Commercial real estate is completely different animal than residential. Loop.net is a popular site where you can review commercial deals. Outside of that you need to find pocket listings and build relationships with brokers and Realtors that list commercial properties. You can also go to http://www.Listsource.com and pull criteria to send out a mailer to a very targeted list of owners.
The answer to your questions depends of what you're looking for. If you wanted limited service distressed hotels, try the Asian American Hotel Owners Association. If you want full service hotels, you will need to check with CMBS servicers like CIII, CW, Midland, KeyBank. Either way, I strongly recommend a broker or partner to help you sort through your REVPar, ADR, and Occupancy projections.
Happy to give a few personal recommendations depending on what you're looking for.
Smith Travel Research (STR.com) has an array of reports and resources that provide insight into hotel industry metrics. There are roughly 7 type of market segments, defining what segment you want to look at will inform what type of metrics you need to look at.
Matt Knight was right on with recommending that you use RevPAR, ADR, and Occupancy history + projections; they are the industry's leading indicators for overall health of property.
I was a hotelier for 9 years and worked with an array of companies at properties across the United States at a 3, 4, and 5 star level. If you have any questions I'd be happy to help.